Hi There. Any help or assistance with my issue will be much appreciated…..997.2 2010 with 38k on the clock.
All running fine. Not used for 3 weeks then went on 100 mile drive. 99 miles of the drive fine and driven fairly leisurely (M25!) and on last mile of trip, put my foot down a bit and then MIL light came on.
Checked with a generic OBD11 reader and got the following codes:
P0204 injector circuit malfunction – cylinder 4
P0270 cylinder 4 injector – circuit low
P0304 cylinder 4 - Misfire detected
So, seems like an injector fault or wiring fault. Thinking it might be ignition problem to that cylinder and knowing coil packs can be an issue, I have swopped spark plug and coil packs over from another cylinder – no change.
Being cylinder 4, it is the easiest to see the injector, so I have check the resistance and it shows 1.4 Ohms (seems low but not a short) and connected (tapped) a 12v signal to it and you can hear the injector opening/clicking.
I have tried tapping the injector with a metal rod to try and free any deposits (but scared to knock it too hard!)
In my mind, it seems like dirt or a dirty injector but I am fairly mechanically minded (changing plugs and coil packs on a 997 isn’t that easy as you know…) but I am really not confident about trying to remove the injector as it looks like a bit of a nightmare.
Any suggestions from anyone before I have to try and replace the injector? (or get someone else to do it for me)
I know I can swop the injectors over to see if the fault moves but the amount of work involved tells me to just replace the injector while I am there. Porsche quote £179.15 for the part 9A1 110 129 10. I am sure I can find the Bosch or whatever OEM part for less if I search……
It is clearly running on only 5 cylinders and I have tried to ‘blast it - Italian tune up’ to clear the problem but no change – and don’t really want to drive it more with the problem. I have reset the codes but it comes on straight away when started again and runs lumpy from startup.
Being 38k miles, a few friends told me it is VERY unlikely to be an injector but I cannot see it can be anything else? Was thinking of buying some archoil cleaner (or similar) but think that might not cure the problem if it is a faulty injector rather than just dirt/deposits in the injector……..and if the injector is not injecting fuel, how will cleaner ‘clean it’ ?
Any suggestions from anyone before I have to try and replace the injector? It looks like a big job! (or get someone else to do it for me) or will a higher spec OBD reader give me more information – is it worth getting an indie to run it up on a ‘proper’ reader or just a waste of time?
Thanks in advance.

Last edited by gerryfrost on Mon Dec 04, 2017 5:54 pm; edited 1 time in total

996ttalotApproved Trader

Joined: 21 Sep 2009Posts: 1312Location: Horley Gatwick

Posted: Sun Dec 03, 2017 2:45 pm Post subject:

On the DFI it is a common issue for an injector to fail - they are under in some cases 150psi unlike the non Dfi which have a lot less pressure.

The recommendation is to replace all injectors on that bank which I disagree with porsche about since I have asked the question about flow matching and they cannot give an answer - surprise surprise - as if I buy 3 injectors all three will be matched - not !

With plugging in PIWIS and since you have done wiring checks the it is most likely that replacing that one injector will resolve.

However I have seen this done and then months later same issue come back - excessive fuel pressure can be a cause of this.

Hi Gerry,
I had a similar issue although we could never get a fault to log, after changing coil packs and plugs the injectors and fuel pump were tested and all passed... after much frustration we did live data logging and found that sporadically i was getting a miss on no.4 when under load, turns out the wire going to the coil pack had chafed and was earthing occasionally when under heavy load.
Not sure if this will help but may be worth a good poke around.
Good Luck_________________Atlas Grey - 997.2 C4S

gerryfrostNewbie

Joined: 04 Jan 2015Posts: 9Location: St. Albans, Herts.

Posted: Mon Dec 04, 2017 6:02 pm Post subject:

Thanks for your help. Used a Noid light today and got a reading to the input of the injector - noid light was flashing away as it should do.....
I read the voltage to the injector and it was showing 3.6volts; i was expecting to see 12v signal to the injector or was the info i was given not correct?
(it is a 997.2 not a gen 1)
Thanks again and any help is appreciated.

DemortEstoril

Joined: 21 Mar 2015Posts: 3502Location: Sussex

Posted: Tue Dec 05, 2017 3:53 pm Post subject:

Perhaps this will help .._________________

7pm - 9pm

injector-1.jpg

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gerryfrostNewbie

Joined: 04 Jan 2015Posts: 9Location: St. Albans, Herts.

Posted: Wed Dec 06, 2017 6:59 pm Post subject:

Thanks for your help.
Don’t suppose anyone knows the OEM product for these injectors? Normally they are found in a search but can’t find anything....continental or bosch and what part number?

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